The tooth is a vital structure of the oral cavity that is responsible for chewing (masticating) food and for providing a pleasing aesthetic appearance. Anatomically, teeth reside within the oral cavity, firmly anchored in the upper jaw (maxilla) or the lower jaw (mandible) within two distinct anatomic regions of the jaws and periodontium or supporting structures. The first anatomic region is the apical inferior portion of the tooth or root, which is connected to the jawbone via an attachment called the periodontal ligament. The portion of the jawbone that is connected to the tooth may be referred to as the bone or hard tissue zone. The second anatomic region is the superior portion of the tooth, called the anatomic or clinical crown, which is superior to the crest of the bone, including the visible portion of the tooth above the gingival line. The anatomic or clinical crown is connected to the jaw in the soft tissue or gingival region of the jawbone referred to as the soft tissue zone. The soft tissue zone forms a soft tissue collar around the neck of the tooth. The gingival surface that surrounds each tooth includes peaks (papillae) and valleys. The soft tissue-tooth attachment is composed of gingival fibers that insert into the superior aspect of the root surface to form the junctional epithelial and connective tissue (sulcular epithelium) attachments and, more specifically, the hemidesmosmal cell attachment to the root and crown surfaces.
The attachment of the gingival soft tissue to the tooth forms a biological adherence or seal between the gingival tissues and the surface of the tooth. This biological seal plays an important role in maintaining the health of the oral cavity by inhibiting or preventing the ingress of oral bacteria and foreign substances through the soft tissue zone/tooth interface to the underlying bone.
The inability to reestablish the biologic seal after the removal of a tooth has many repercussions to bone and soft tissue regeneration and on soft tissue changes to both the macro- and micro-anatomy of the gingiva. For example, the soft tissue zone plays an essential role in maintaining and preserving dental aesthetics. The spatial relationship of the teeth, the color of the teeth, and the soft tissue gingival architecture are important factors in maintaining desirable dental aesthetics. The loss or alteration of any of these factors generally leads to an inferior aesthetic outcome and/or a potential risk of disease for the patient.
In an era of dentistry driven by high aesthetic demands and standards, post-extraction tissue loss can pose a considerable aesthetic, surgical, and/or restorative challenge. For example, the loss of gingival attachment within the soft tissue zone may lead to the irreversible loss of the interdental papillae and the gingival architecture surrounding a prosthetic tooth or dental restoration. In vivo studies report up to about 3-6 mm of bucco-lingual volumetric remodeling within the first six months following extraction of non-molar teeth. This dimensional change is attributed to soft tissue collapse in the edentulous space immediately following tooth extraction, which can significantly alter the midfacial gingival architecture and/or create an aesthetically displeasing “shadowing” effect around the final restoration. There are currently no predictable surgical techniques available to correct the gingival changes to vertical height and horizontal dimensions of the interdental papillae after tooth removal.
As such, it is critical to consider proper tissue (e.g., periodontal tissue) management during the treatment planning phase to achieve consistent treatment outcomes and, specifically, to maintain pre-extraction gingival morphology and architecture of the edentulous ridge. This concept is often referred to as guided soft tissue preservation.
Several procedures have been proposed to assist in addressing the disadvantages associated with post-extraction tissue loss. Surgical interventions include extraction socket preservation techniques, immediate implant placement, and alveolar bone grafting, which are used to minimize significant post-extraction hard and soft tissue dimensional changes. However, immediate implant placement and bone grafting may not be viable treatment options in certain clinical situations such as inadequate buccal plate volume post-extraction, patients with medical limitations, limited time, and/or limited finances, or the like. Furthermore, existing devices and methods have been generally unsuccessful in providing a minimally invasive technique to reestablish a biologic seal surrounding a tooth-extraction site after tooth removal.
For example, barrier membranes for guided tissue bone regeneration (GTR) have been used to assist in maintaining, preserving, and/or regenerating lost bone after, e.g., periodontal disease. Barrier membranes generally assist in creating a protective barricade by inhibiting or preventing the migration of unwanted cells (e.g., connective tissue cells) to the post-extraction socket such that the post-extraction socket can be refilled with bone cells (e.g., osteoblasts) known to assist with bone growth.
One disadvantage associated with using barrier membranes is the direct exposure of the barrier membrane to the oral environment, which may be due to the lack of an effective soft tissue zone-tooth seal. Additionally, once the membrane has been exposed to the oral environment, bacteria may colonize on the surface of the membrane, thereby potentially leading to infection and/or causing the bone to fail to regenerate. Such exposure may also lead to plaque accumulation on the surface of the membrane that is difficult, if not impossible, to clean/remove.
Collagen-type membranes may be less prone to plaque accumulation, but they may be more susceptible to dissolution (dissolving) once exposed to salivary enzymes, which may break down the collagen matrix after only a few days or weeks of exposure.
Some existing periodontal bone regeneration methods include inserting hard-tissue graft material (e.g., bone replacement substances) into the post-extraction socket. Non-limiting examples of bone replacement substances include autografts, allografts, xenografts, alloplastic grafts, and/or a variety of bone replacement and cell stimulating materials that may include bone morphogenic proteins (BMPs), stem cell derivatives, platelet rich proteins (PRPs) derived from a patient's blood, and/or other biologic sources. One disadvantage associated with using bone replacement substances is the inability to contain and protect the substances from exposure to foreign substances during the critical healing phase due to an ineffective soft tissue zone-tooth biologic seal after tooth removal.
Another problem that often occurs after tooth extraction is the anatomic and physical collapse of the extraction socket and ridge. This collapse may occur with or without elevation of a mucoperiosteal flap. In some instances, ridge collapses ranging from about 2.2 mm (e.g., in cases where the flap was not elevated) to about 5.9 mm (e.g., in cases where the flap was elevated) have been reported. The use of a hard-tissue (e.g., bone) graft material placed in the extraction socket after tooth removal has been shown to be useful in reducing ridge collapse, but it is not without disadvantages. For example, bone grafts placed in extraction sockets often prematurely absorb, depending upon the type of graft used.
It is generally difficult to properly adapt the gingival or gum side of a temporary pontic restoration (e.g., coronal pontic portion) as part of a fixed dental prosthesis (FDP), whether tooth-borne or implant-borne. One obstacle is due to the fact that, after tooth removal, there is often a significant amount of localized bleeding into the extraction socket. The resultant formation, which may be described as a “liver” blood clot, may become a physical barrier, blocking provisional pontic restoration material from being properly adapted to the undersurface of the FDP. As such, the undersurface of the temporary pontic restoration area may not accurately mimic and represent the extraction socket site. Consequently, the undersurface of the temporary pontic restoration is often formed freehand by “eyeballing” the extracted socket site, which may or may not accurately represent the site. However, if properly formed, the undersurface of the temporary pontic restoration can physically support the mucosal soft tissues, thereby generally maintaining the shape of the extraction socket.
Pontics are advantageous because they emerge from the gingival tissues and generally mimic the cosmetic appearance of a natural tooth. Therefore, it is important to generally maintain the socket anatomy with the associated hard and soft tissues after tooth extraction to preserve the aesthetic appearance of the mucosal gingival tissues and their relationship to the pontic.
The devices and methods described herein assist in generally reestablishing the important biologic seal after tooth removal and in preserving the aesthetic and anatomic architecture of the tissue zone.